Chassis, generic

C0020 ABS Pump Motor Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

Covers the electric pump (return) motor of the ABS hydraulic unit and its control circuit. The motor drives the piston pump that returns brake fluid from the low-pressure accumulators and builds pressure for ABS, traction and stability interventions. The control module commands the motor and monitors the drive circuit and motor-run feedback; it sets the code for an open or shorted motor circuit, a seized motor or a run signal that does not match the command. RAM assigns code C0020-01 to a general electrical failure of the ABS pump-motor control on its 2500 and 3500 trucks. A fault disables ABS and the stability functions; the ABS lamp illuminates and base braking remains.

Likely causes

Pump motor seized or windings failed
Open or shorted motor supply or ground
Brake control module driver fault

Symptoms

  • ABS warning lamp on
  • ABS, traction and stability control disabled
  • No pump noise during self-test

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€400–1,900
Time1.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

abs pump motorabs control modulepump motor relaypower supply wiring

Related codes

C0021C0010C0014

References: static.nhtsa.gov, en.wikipedia.org.